If you happen to be in Pennsylvania, you arent far from a great hiking or backpacking trail or area. A couple of top areas include Upper Delaware Scenic and Recreational River and Valley Forge National Historical Park.
AllTrails.com has a handy feature that permits you to browse for just the ideal trail to explore this weekend.
Gorp has a great list of places to go as well as tips and guides.
Trails.com — browse thousands of hiking trails and unlimited topo maps. You can try it for free.
Personal trail info from the West Rim Trail in northern Pennsylvania.